/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jms.remoting;

import org.springframework.aop.framework.ProxyFactory;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;

/**
 * FactoryBean for JMS invoker proxies. Exposes the proxied service for use
 * as a bean reference, using the specified service interface.
 *
 * <p>Serializes remote invocation objects and deserializes remote invocation
 * result objects. Uses Java serialization just like RMI, but with the JMS
 * provider as communication infrastructure.
 *
 * <p>To be configured with a {@link javax.jms.QueueConnectionFactory} and a
 * target queue (either as {@link javax.jms.Queue} reference or as queue name).
 *
 * @author Juergen Hoeller
 * @see #setConnectionFactory
 * @see #setQueueName
 * @see #setServiceInterface
 * @see org.springframework.jms.remoting.JmsInvokerClientInterceptor
 * @see org.springframework.jms.remoting.JmsInvokerServiceExporter
 * @since 2.0
 */
public class JmsInvokerProxyFactoryBean extends JmsInvokerClientInterceptor
        implements FactoryBean<Object>, BeanClassLoaderAware {

    @Nullable
    private Class<?> serviceInterface;

    @Nullable
    private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();

    @Nullable
    private Object serviceProxy;


    /**
     * Set the interface that the proxy must implement.
     *
     * @param serviceInterface the interface that the proxy must implement
     * @throws IllegalArgumentException if the supplied {@code serviceInterface}
     *                                  is not an interface type
     */
    public void setServiceInterface(Class<?> serviceInterface) {
        Assert.notNull(serviceInterface, "'serviceInterface' must not be null");
        Assert.isTrue(serviceInterface.isInterface(), "'serviceInterface' must be an interface");
        this.serviceInterface = serviceInterface;
    }

    @Override
    public void setBeanClassLoader(ClassLoader classLoader) {
        this.beanClassLoader = classLoader;
    }

    @Override
    public void afterPropertiesSet() {
        super.afterPropertiesSet();
        Assert.notNull(this.serviceInterface, "Property 'serviceInterface' is required");
        this.serviceProxy = new ProxyFactory(this.serviceInterface, this).getProxy(this.beanClassLoader);
    }


    @Override
    @Nullable
    public Object getObject() {
        return this.serviceProxy;
    }

    @Override
    public Class<?> getObjectType() {
        return this.serviceInterface;
    }

    @Override
    public boolean isSingleton() {
        return true;
    }

}
